New Delhi: The cut in vehicular emission due to rolling out of the odd-even scheme has resulted definitive decline in levels of PM2.5 pollutants, Delhi Government said yesterday while claiming success of the restrictions unveiled on January 1.

The government said data of pollutants collected from over 55 locations showed a clear trend of improving air quality in several areas across the city and that there has been a positive impact of the odd-even scheme.

"According to the scientists of the Delhi Pollution Control Committee (DPCC), 80 per cent of PM2.5 air pollution is caused by vehicular traffic and reduction in its levels, even in outer areas of Delhi shows that reduction of four wheeled vehicles on roads since the New Year Day is having a positive impact", the government said in a statement.

However, a report by IIT Kanpur had said vehicular pollutions contribute to around 25 per cent of PM2.5 concentrations during winters which comes down to 9 percent during summers.

It said the ambient air data collected by DPCC through mobile dust samplers using Light Scattering Technique at 20 locations in peripheral areas of Delhi on January 4 showed a clear declining trend in the levels of PM2.5.

The major source of PM2.5 pollutant is vehicular pollution. Transport Minister Gopal Rai had asked for data collection from peripheral areas of Delhi to ascertain the impact of NCR towns on air pollution of Delhi.